I Distribution • Global Village • B. Highest density – • 4 clusters • common characteristics • C. Lowest density • common characteristcs Ch 2 - Population
Ecumene, 5000 B.C. A.D. 1
D. Population density 1. Arithmetic 2. Physiological 3. Agricultural
II. How growth is measured • Birth rate Crude birth (CBR), total fertility (TFR) • Mortality Crude death (CDR), infant morality C. Natural increase (CBR-CDR)/10 Doubling rate D. Life expectancy
Crude Birth Rates Crude Death Rates Fig. 2-8: The crude birth rate (CBR) is the total number of births in a country per 1000 population per year. The lowest rates are in Europe, and the highest rates are in Africa and several Asian countries.
Natural Increase Rates Fig. 2-7:The natural increase rate (NIR) is the percentage growth or decline in the population of a country per year (not including net migration). Countries in Africa and Southwest Asia have the highest current rates, while Russia and some European countries have negative rates.
Life Expectancy at birth Fig. 2-11: Life expectancy at birth is the average number of years a newborn infant can expect to live. The highest life expectancies are generally in the wealthiest countries, and the lowest in the poorest countries.
III. Demographic Transition model • Stage 1- Low growth epidemiologic transition – pestilence, famine • Stage 2- High growth epid. tran. – stage of receding pandemics C. Stage 3 - Moderate growth epid. tran. – degenerative, human-created diseases D. Stage 4 - Low growth delayed degenerative disease re-emergence of infectious/parasitic disease
Stage 1 Epidemiologic transition – pestilence & famine Stage 2 – e.t. “receding pandemics
Stage 4 – e.t. “delayed degenerative disease” Stage 5- e.t. “re-emergence of infectious/ parasitic disease”
IV. Population pyramids • Structure- age, gender • Shape • Explosive growth • Zero growth 3. Negative growth (implosion)
Fig. 2-16: Population pyramids can vary greatly with different fertility rates (Laredo vs. Honolulu), or among military bases (Unalaska), college towns (Lawrence), and retirement communities (Naples).
Advantages and disadvantages • explosive growth • negative growth • Dependency ratio – • # of people under age 15 and • over age 64 yrs, compared to • # people in work force
Gender imbalance • India and China
Is there an overpopulation problem? A. Malthus Population growth & food supply B. Boserup Intensification of agricultural production C. Current trends C. Absolute v. Relative scarcity
Food & Population, 1950-2000Malthus vs. Actual Trends Fig. 2-20: Malthus predicted population would grow faster than food production, but food production actually expanded faster than population in the 2nd half of the 20th century.
Use of Family Planning Fig. 2-22: Both the extent of family planning use and the methods used vary widely by country and culture.